In this study, an unstable rock slope has been investigated. To evaluate the stability of the pentahedral rock wedge with multi-slip surfaces, an approach based on the limit equilibrium method has been used. The slope has been divided into two parts for the establishment of the model: an upper wedge block and a lower pentahedron block. Namely, a three-dimensional space problem can be resolved into a local equilibrium problem of several sub-blocks. Then, the geometric parameters can be determined, and the mechanical analysis can be carried out. Finally, the minimum safety factor can be calculated by using the optimization method. This proposed approach has been applied to analyze the stability of the unstable rock slope before and after reservoir impoundment. The results show that the safety factor is significantly smaller after reservoir impoundment. The safety factor can meet the safety control standards of specifications without considering the extreme conditions of combined rainstorm and seismic force under the proposed reservoir water level.

在这项研究中，研究了一个不稳定的岩石边坡。为了评估具有多滑动面的五面体岩石楔块的稳定性，使用了一种基于极限平衡法的方法。为了建立模型，斜坡被分为两部分：上楔块和下五面体块。即，一个三维空间问题可以被分解为几个子块的局部均衡问题。然后，可以确定几何参数，并可以进行力学分析。最后，可以使用优化方法计算最小安全系数。该方法已应用于分析水库蓄水前后不稳定岩石边坡的稳定性。结果表明，水库蓄水后安全系数明显变小。在拟建库水位下，不考虑暴雨地震联合作用的极端条件，安全系数满足规范的安全控制标准。